The Codex stored in the National Museums department of manuscripts and early prints originated in the late 15th and early 16th century Czech Lands.
The impetus for the drawing of this document came from the Utraquist Bohuslav of Cechtice. The manuscript bears rich and extensive illumination.
In some parts, the pictorial decorations dominate the text.
The manuscript primarily contains theological treatises that are to highlight the discrepancy between the early Church and the Church of the time of Master John Huss.
The illuminations depict, for example, the clergys dissolute lifestyle, or criticise the selling of indulgencies.
Almost the entire Codex is written in Czech, with only a small part in Latin.

The manuscript is not the work of a single man. Several scribes participated in its writing.
The illuminations too were the work of several people, belonging to a 16th century illumination workshop led by Janícek Zmiletı of Písek,
to whom the most beautiful illuminations are attributed.
It was standard practice in illumination workshops for the leading artist to create the most important illuminations and leave the others to his colleagues.
Several painters might have been involved in creating one image. One painter might have worked on the borders, for example, while another concentrated on the background.
It is assumed that several works similar to the Jena Codex were created in the 15th century.
However, only one more manuscript comparable in its content has survived to this day - the Göttingen Codex.
Although the decorations of the Jena Codex are richer and of better quality than those of the Göttingen Codex,
what both works have in common is satirical text directed against the state of the contemporary Church. The figurative scenes are very appropriate to the text.
Source: Muzeum 3000